Hi Kevin!!
Try some 11-4 through 12-4 props. A lot will depend on the weight of the airplane. The gray Thinder Tiger props have worked well, a 11- 4.5, I think it is, APC 11-4 and 11-4.5, and APC 12.25-3.75. Those will get you started and you can test others from there. It will be a high RPM run in the 9500 to10,000 RPM range in the wet -2 mode. The Vector isn't a very big model but they seem to come out in the upper 40 ounce to 50 ounce range. HAVE FUN!!
Dan McEntee